The chlorosis is not a disease per se. It is in fact a physiological impairment plants usually due to deficiency in minerals or trace elements, or too high a concentration in the soil of active limestone.
The latter hinders or even prevents the roots of the plant to assimilate certain minerals such as iron.
Symptoms: how to recognize chlorosis?
The symptoms of chlorosis are very characteristic:
- The growth of the plant is slow down, in particular because of the decrease in photosynthesis and therefore chlorophyll.
- We then see a yellowing leaves. It first localizes between the veins of the leaf blade, then generalizes over its entire surface.
- Evolution is progressive. The old leaves are the first to be affected; then come the youngest.
Depending on the type of deficiency, the symptoms may vary.
- Iron deficiency: also called ferric chlorosis, it manifests itself in the same way as general symptoms. In contrast, in this case the veins remain green and only the leaf blade becomes discolored.
- Magnesium deficiency: after turning yellow, the leaves turn brown and then fall.
- Phosphorus deficiency: again, the leaves turn brown. In addition, if the plant has fruits, they become deformed.
- Nitrogen deficiency: the leaves become completely discolored. This time it is the veins that discolor more than the leaf blade.
Which plants are the most affected?
All plants can be affected. However, the plants acidophilus (like azaleas, hydrangeas, rhododendrons, etc.) or calcifuges (roses for example) are a little more sensitive than others because of their requirement on the nature of the soil. They are therefore more easily affected by ferric chlorosis due to too much limestone in the soil.
Prevention of chlorosis
Ideally, if you can, do a soil analysis in your garden to prevent chlorosis. You will thus be able to know if your soil contains too much limestone or if it is deficient in minerals and trace elements essential for photosynthesis (magnesium, potassium, zinc, nitrogen, phosphorus, iron, etc.).
Smart tip : some garden centers can carry out this soil analysis. Do not hesitate to inquire with one of them.
The ferric chlorosis is the easiest to prevent. It is sufficient to maintain a pH below 6.5. To do this, you can:
- apply a thick layer of maritime pine bark which will maintain acidity soil as it decomposes;
- privilege rainwater to water your plants (this advice is even more important if you live in an area with very hard water).
Treatment of chlorosis
General case: plants in the ground
When the causes of chlorosis are determined, there are several ways you can take action:
- If it is a lack of nitrogen, spread a manure organic like dried blood or bone meal in early spring.
- In case of ferric chlorosis, apply iron chelate in March-April, just before the resumption of vegetation.
- In general, a contribution of compost helps increase iron, zinc, and nitrogen content in the soil.
Special cases: potted plants
This situation is probably the easiest to manage. Indeed, the problem being related to the nature of the soil, chlorosis is perhaps the sign that it is time to change the substrate of your plants.
If you have recently repotted your plants and they are still prone to chlorosis, the easiest way is to follow the treatment tips for plants in the ground.
Another solution, make a regular intake fertilizer rich in minerals and trace elements. You can also water with a anti-chlorosis product.
Smart tip : A grandmother's remedy for chlorosis (especially ferric chlorosis) consists of incorporating rusty objects into the earth.